Cleavage\ˈklē-vij\:The depression between a woman's breasts especially when made visible by a low-cut neckline.

Started in 2002, National Cleavage Day is an annual celebration held on March 30, created by the brassiere marketer Wonderbra. The holiday is celebrated in the UK, South Africa, and the US.

Wonderbra claims that National Cleavage Day was initiated as an attempt to solemnize women's independence and power in the modern world. Wonderbra PR claims "It gives women a chance to be beautiful and glow in the furtive, yet appreciative, glances their cleavage evokes from men". They also explained "It gives men a legitimate reason to stare at boobs."